Fuel systems for internal combustion engines are usually designed so that fuel filter exchange (replacement) involves emptying the fuel line between the outlet of the filter housing and the cylinder head. Because the fuel is an environmentally harmful substance, it is necessary that it be collected to avoid spillage. Such fuel filter exchange is a common service action, especially on heavy diesel engines that are used a great deal. It is usual for fuel systems for diesel engines to be provided with a bleed nipple and a hand pump which can be used when air bleeding and refilling of the drained line with fuel is carried out. Typically, before the engine is started after such a filter exchange, a large number of strokes of the hand pump are required, and it is necessary to open one or more bleed nipples in order to remove the quantity of air present in the new filter. This involves expensive workshop time and also a risk of fuel spillage because the abovementioned nipples are generally not closed before the fuel flows.
There are fuel systems with devices that can be used to automate the procedure for removing air (see, for example, U.S. Pat. No. 5,534,161). This patent describes a pump which can be driven in two directions by means of a microprocessor and that can be used for removing water from the fuel channel. This device, however, can only facilitate the procedure for bleeding air from the fuel system, and further actions are required in order to remove air from the high-pressure side of the system. Inclusion of this type of device therefore requires that the number of components in the fuel system be increased without fully solving the problem of facilitating the bleed procedure.